Fuel injection pumps



Nov. 17, 1964 F. MARTYN ETAL 3,157,173

FUEL INJECTION PUMPS Filed June 29, 1962 United States Patent Office3,157,173 Faten ted Nov. 17, 1964 3,157,173 FUEL WEECTIGN PUMPS LaurenceFrederic Martyn, Waiton' on Thames, and

Michael Pole, fiouthail, England, assignors to Mono- Cam Limited,London, England, a company of Great Britain Filed June 29, 1962, Ser.No. 2%,436 Claims priority, application Great Britain, June 29, 1961,

7 (Claims. (Ci. its-14s This invention relates to fuel injection pumpsfor in ternal combustion engines particularly though not ex clusively,compression-ignition engines. It is concerned with improvements in suchpumps of the kind (hereinafter referred to as the kind specified)comprising one or more piston and cylinder pumping assemblies in whichthe effective length of the delivery stroke of the or each piston iscontrolled by pressure-responsive governor means which is exposed duringthe injection stroke of a piston to a fuel pressure and which isarranged to move under the influence of said fuel pressure against theeffect of spring means to place the cylinder in communication with theinlet side of the pump, the fuel tank or like low pressure region whenthe engine speed exceeds that for which the pump is set.

In the specification filed in respect of the co-pending application No.8,763 dated February 15, 1960, now Patout No. 3,075,509, there isdescribed a fuel injection pump of the kind specified in which the fuelpressure to which the governor means is exposed at the commencement ofan injection stroke is a function of the period of time between thecommencement of the injection stroke and the end of the immediatelypreceding injection stroke thereby ensuring that the fuel pressure towhich the governor means is exposed is a function of the mean enginespeed over a period of time longer than the injection period. This isachieved by forming the governor means as a substantially cylindricalvalve body slidable in a sleeve and arranged to place the pumpingcylinder in communication with the inlet side of the pump or like lowpressure region at a predetermined displacement of the valve bodyrelative to the sleeve. One end of the valve body is exposed to a volumeof fuel displaced during a pumping stroke of the piston through anonreturn valve to displace the valve body from a starting position andallowing the volume of fuel to leak away through a restriction to a lowpressure region during the period between the end of the injectionstroke and the commencement of the next injection stroke so that thevalve body returns towards its starting position during this period oftime under the influence of the spring means. The starting position towhich the valve body has returned at the commencement of the nextinjection stroke and hence the distance through which the valve bodyrequires to be displaced before placing the pumping cylinder incommunication with the low pressure region is thus a function of theperiod of time between the commencement of the injection stroke and theend of the preceding injection stroke and hence a function of the enginespeed. It will be appreciated that the pressure of the fuel to which theone end of the valve body is subjected to a function of the pressure ofthe spring means exerted on the valve body tending to return it to itsstarting position and hence is a function of the magnitude of thedisplacement of the valve body and is thus a function of the period oftime between the end of an injection stroke and the commencement of thenext injection stroke. Although the maximum displacement of the valvebody is, in practice, only of the order of 2.5 mm., this can result in adifference of pressure exerted by the spring means between the two endpositions of the valve body of several pounds per square inch. We havenow found that the governing characteristics of the fuel injection pumpof our prior proposal can be considerably improved by arranging for thefuel to which the one end of the valve body is exposed to leak awaythrough a restriction which is only operative during that part of aninjection stroke which occurs after the pumping cylinder has been placedin communication with the low pressure region and injection has ceased,thereby modifying the stroke of the valve body.

According .to the present invention there is provided a fuel injectionpump of the kind specified wherein the governor means comprises asubstantially cylindrical valve body having one end arranged to beexposed to said fuel pressure and displaceable in a sleeve against theeffect of the spring means to place the pumping cylinder incommunication with the inlet side of the pump, the fuel tank or like lowpressure region at a predetermined displacement of the valve body withinthe sleeve, a first restriction between said one end of the body and thelow pressure region and operable during the period between the end of aninjection stroke and the commencement of the next injection stroke topermit a restricted escape of fuel from said one end of the valve bodyand a second restriction between said one end of the valve body and thelow pressure region and operable to permit a restricted escape of fuelfrom said one end of the valve body to the low pressure region duringthat part of an injection stroke which occurs after the pumping cylinderhas been placed in communication with the inlet side of the pump andinjection has ceased.

Reference is now made to the accompanying drawings which illustrate anembodiment of the present invention here given by way of example and inwhich:

FIG. 1 is a sectional elevation View, and

FIG. 2 is an enlarged view of a portion of FIG. 1.

In the embodiment illustrated a reciprocatory rotating piston isindicated at 1, the means for achieving the reciprocating and rotarymotion and which may include a cam follower mechanism not being shown.This piston 1 has an enlarged annular part 2 and a piston head portion3, the enlarged part 2 cooperating with a cylindrical chamber 4 and thepiston portion 3 sliding within a cylindrical chamber indicated at 5. Alow pressure fuel inlet to cylindrical chamber 4 is shown at 6 and a lowpressure fuel inlet to the cylindrical chamber 5 is shown at 7. Theupper part of the cylindrical chamber .5 is in communication with aninjection conduit 8 through a conduit indicated at 9 which extendsaxially of the piston 1 and then extends radially to terminate in a flatportion which communicates with the inner end of the injection conduit 8when the piston 1 has attained the requisite position in itsreciprocatory and rotational motion. It will be understood that aseparate conduit 8 is provided for each cylinder of the engine to whichfuel is to be fed, the conduits 8 being equi-angularly disposed aboutthe axis of the piston 1.

A path for fuel from the cylindrical chamber 4 is provided by a passage10, this path including a non-return valve indicated at 11. A returnpath for fuel is provided by a passage 12, the passages 10 and 12opening through the wall of a sleeve defining a cylindrical chamber 13which is disposed with its axis transverse to the axis of cylindricalchamber 5. A governor member is provided by a cylindrical governor valvebody 14 which is housed in sliding relationship in the cylindricalchamber 13. Located to the right hand side of the governor valve 14 (asseen in FIG. 1) is a terminating plug 15 the position of which isadjustable by screw 16 with respect to the lateral extent of thecylindrical chamber 13. The end of the plug 15 adjacent the governorvalve 14 is formed with two lateral projections 17, the governor valvemember 14- bearing against these lateral projections 1'7 in the limitinginner or extreme right hand position of the governor valve body 14. Thelimiting inner end position of the valve body 14 is such that thepassage it is always open to the space between the inner end of thevalve body 14- and the plug 15 so that fuel is supplied to this space bythe enlarged annular part 2 of the piston l on each injection stroke todisplace the governor body 14 outwards.

The governor valve 14 has a central conduit 13 extending from its endadjacent the plug 15 to a cooperating radially extending orifice 19. Theradially extending orifice 1Q terminates in a fiat 20 which has butslight clearance between its surface and the inner surface of thecylindrical chamber i3 and defines a restriction which is operative whenthe flat 26 clears the outer or left-hand end of the sleeve defining thechamber 13 to permit a restricted escape of fuel from the space at theinner end of the valve body 14. This portion of FIG. 1 is indicated inenlarged view in FIG. 2.

The governor valve 14 has a reduced diameter portion 21 and a spillpassage 22 is formed in the block in which the cylindrical chamber 13 isprovided. A return spring 23 biases the governor valve 14- towards thelimiting right hand inner position and the lateral projections 17 of theplug 15. A cut-away portion 24 is provided in the cylindrical wall ofthe governor valve 14 at the inner end thereof to form a restrictionbetween this cut-away portion 24 of the governor valve and the opposedpart 25 of the cylindrical chamber 13, this restriction being, incross-section, defined by a circular are part of the wall of the chamber13, i.e. 25, and by the wall of the cut-away portion 24 which iseccentric with respect to the axis of the valve body 14 so that therestriction arTorded by the cut-away portion 24 is dependent upon theangular adjustment of the governor valve 14, the conduit 12 opening tothe circular are part 25 of the chamber 13. A lever 26 is provided foradjusting the rotational setting of the governor valve 14 in thecylindrical chamber 13. A conduit 27 extends from the upper part ofcylindrical chamber 5, and opens into the chamber 13 at location such asto be placed in communication with the spill passage 22 by the reduceddiameter portion 21 of the valve body 14 when the latter assumes apredetermined position within the chamber 13. The flat 20 is so locatedin relation to the reduced diameter portion 21 and the passages 22 and27 so as to clear the end of the sleeve defining the chamber 13 andpermit a restricted escape of fuel from the inner end of the valve body14 only after the pumping cylinder 5 is placed in communication with thespill passage 22.

In operation fuel from a low pressure gallery is fed via inlet 7 to theupper part of cylindrical chamber 5 and via inlet 6 to the cylindricalchamber 4-. With upward reciprocatory motion of the piston 1, afterclosure of the inlet port 7, the fuel above piston head portion 3 issubjected to pressure and is injected via the conduit 9 to the injectionconduit 8 and thence to the respective engine cylinder in dependenceupon the angular position of the piston 1. The upward movement of thepiston 1 also causes the fuel inlet 6 to be covered by the enlargedannular part 2 and the fuel in the cylindrical chamber 4 is thencepumped up via the conduit 10 to the space in the chamber 13 at the innerend of the valve body 14' to displace the latter outwardly against thespring 23, the ball valve 11 only lifting from its seat during aninjection stroke.

At a predetermined position of the governor valve 14 in the chamber 13,the pumping cylinder 5 is placed in communication with the spill passage22 and injection ceases. After injection ceases and during the remainderof the pumping stroke fuel continues to be displaced from the chamber 4to the space at the inner end of the valve body 14- and the lattercontinues its outward displacement to cause the fiat 20 to clear the endof the sleeve defining 4: the chamber 13 and allowing a restrictedescape of fuel from the inner end of the valve body through the passages18 and 19 and the fiat 20 to the low pressure side and thereby modifyingthe stroke of the valve body 14 after the termination of injection, thevalve body 14 continuing its outward displacement throughout theinjection stroke.

During the period between the end of the injection stroke of the piston1 and the commencement of the next injection stroke, the valve 11 closesthe passage 10 and fuel leaks away from the space at the inner end ofthe valve body through the restriction afforded by the cut away portion24 and the passage 12 so that the governor body 14 returns towards itsinner end position under the influence of the spring 23 and, at thecommencement of the next injection stroke, has returned to a position inthe chamber 13 which is a function of the period of time between thecommencement of the injection stroke and the end of the immediatelypreceding injection stroke and hence of the engine speed. The pressureof the fuel in the space at the inner end of the valve body 1 is thusalso a function of the period of time referred to and hence of theengine speed. Thus, if the engine speed is greater than that for whichit is set, the period of time referred to will be less than it shouldbe, the valve body 14 will have returned a shorter distance towards itsinnermost position than it should have and the valve body 14 will have ashorter outward displacement before the reduced diameter portion 21places the pumping cylinder 5 in communication with the spill passage 22and hence a lesser quantity of fuel will be injected into the enginecylinder.

The provision of the restricted escape of fuel by way of the flat 25)which is operative after injection has ceased until the end of theinjection stroke, imparts a means of controlling the governingcharacteristics. With no escape of fuel, the amplitude of the valvemotion is constant under all governing conditions so the zone ofoperation of the valve changes with engine load. Under such conditions,however, the governing is isochronous. it has been found that therestricted leak provides a means of controlling the speed range orrun-out of the governor between full load and no load acceptable to themajority of applications without altering the amplitude of the valve bymore than 5%. When a change of engine load occurs the displacement/timediagram of the valve changes its zone during the eriod of change ofspeed, but remains substantially unaltered in characteristic in whateverzone it is working.

The restriction afforded by the flat 20 controls the rate of rise of thefuel to which the inner end of the valve body is exposed after injectionhas ceased and thus controls the difference between no load speed andfull load What we claim is:

1. A fuel injection pump for an internal combustion engine comprising ahousing, a cylinder within said housing, a piston reciprocable withinsaid cylinder by said engine to form a pumping assembly having a pumpingstroke of the piston during at least a part of which fuel is injectedinto an engine cylinder and a suction stroke during which no fuel isinjected to said engine cylinder, an enlargement of said pumpingcylinder providing an auxiliary cylinder, an enlargement of said pistonreciprocable in said auxiliary cylinder by said engine, a first fuelinlet passage opening into said pumping cylinder at a locationblanked-off by said pumping piston during a pumping stroke to define thecommencement of the period of injection of fuel to said engine cylinderand opening to the exterior of said housing for connection to a lowpressure fuel supply, a second fuel inlet passage opening into saidauxiliary cylinder at a location blanked-off by said auxilairy pistonduring a pumping stroke to generate a fuel pressure in said auxiliarycylinder as a function of engine speed and opening to the exterior ofsaid housing for connection to said low pressure fuel supply, a governorsleeve in said housing, a first pressure transmitting passage extendingbetween said auxiliary cylinder and said sleeve to transmit saidgenerated fuel pressure to said sleeve, a non-return valve in said firstpressure transmitting passage to prevent escape of said generated fuelpressure from said sleeve through said first pressure transmittingpassage to said auxiliary cylinder during a suction stroke of saidpumping piston, a second pressure transmitting passage extending fromsaid sleeve to said auxiliary cylinder to permit the escape of saidgenerated fuel pressure from said sleeve during the period of timebetween the end of a pumping stroke of said pumping piston and the cornmencement of the next succeeding pumping stroke of said pumping piston,a first restriction associated with said second pressure transmittingpassage to control the escape of said generated fuel pressure from saidsleeve during said period of time whereby the fuel pressure in saidsleeve at the commencement of the next succeeding pumping stroke of saidpumping piston is a function of said period of time, a third pressuretransmitting passage opening to said sleeve, a fourth pressuretransmitting passage extending from said pumping cylinder and opening tothe interior of said sleeve at a first location, a fifth passagecommunicating with the exterior of said housing and opening to theinterior of said sleeve, a governor valve body displaceable in saidsleeve away from an end position under the influence of said generatedfuel pressure and operable to place said fourth and fifth passages incommunication with each other upon displacement beyond a firstpredetermined distance from said end position to terminate injection andto place said third passage in communication with the exterior of saidhousing upon displacement beyond a second predetermined distance fromsaid end position to permit escape of said generated fuel pressure, saidsecond predetermined distance being greater than said firstpredetermined distance, a second restriction associated with said thirdpassage to restrict the escape of said generated fuel pressure throughsaid third passage and spring means opposing displacement of said valvebody from said one end position and operable to move said valve bodyduring said period of time to a starting position at the commencement ofsaid next succeeding pumping stroke which starting position is afunction of said period of time.

2. A fuel injection pump for an internal combustion engine comprising ahousing, a cylinder within said housing, a piston reciprocable withinsaid cylinder by said engine to form a pumping assembly having a pumping stroke of the piston during at least a part of which fuel isinjected into an engine cylinder and a suction stroke during which nofuel is injected to said engine cylinder, an enlargement of said pumpingcylinder providing an auxiliary cylinder, an enlargement of said pistonreciprocable in said auxiliary cylinder by said engine, a first fuelinlet passage opening into said pumping cylinder at a locationblanked-off by said pumping piston during a pumping stroke to define thecommencement of the period of injection of fuel to said engine cylinderand opening to the exterior of said housing for connection to a lowpressure fuel supply, a second fuel inlet passage opening into saidauxiliary cylinder at a location blanked-off by said auxiliary pistonduring a pumping stroke to generate a fuel pressure in said auxiliarycylinder and opening to the exterior of said housing for connection tosaid low pressure fuel supply, a governor sleeve in said housingcommunicating at one end with the exterior of said housing forconnection to said low pressure fuel supply, a first pressuretransmitting passage extending between said auxiliary cylinder and theother end of said sleeve opposite to said one end to transmit saidgenerated fuel pressure to said sleeve, a non-return valve in said firstpressure transmitting passage to prevent escape of said generated fuelpressure from said sleeve through said first pressure transmittingpassage to said auxiliary cylinder during a suction stroke of saidpumping piston, a second pressure transmitting passage extending fromsaid other end of said sleeve to said auxiliary cylinder to permit theescape of said generated fuel pressure from said sleeve during theperiod of time between the end of a pumping stroke of said piston andthe commencement of the next succeeding pumping stroke of said pumpingpiston, a first restriction associated with said second pressuretransmitting passage to control the escape of said generated fuelpressure from said sleeve during said period of time whereby the fuelpressure at said other end of said sleeve at the commencement of saidnext succeeding pumping stroke of said pumping piston is a function ofsaid period of time, a third pressure transmitting passage extendingfrom said pumping cylinder and opening to the interior of said sleeve ata first location intermediate the length thereof, a fourth passagecommunicating with the exterior of said housing and opening to theinterior of said sleeve at a second location intermediate the lengththereof, a governor valve body disposed in said sleeve with one endexposed to said generated fuel pressure and displaceable away from saidother end of said sleeve under the infiuence of said generated fuelpressure, a cut-away portion intermediate the length of said valve bodyoperable to place said third and fourth passages in communication toterminate injection upon a first predetermined displacement of saidvalve body away from said other end of said sleeve, a second restrictiondefined between said valve body and the Wall of said sleeve andpermanently in communication with said one end of said valve body andoperable upon a second predetermined displacement of said valve bodyaway from said other end of said sleeve to place said one end of saidvalve body in communication with said one end of said sleeve to permit arestricted escape of said generated fuel pressure, said secondpredetermined displacement being greater than said first predetermineddisplacement and spring means opposing displacement of said valve bodyunder the influence of said generated fuel pressure to move said valvebody during said period of time to a starting position at thecommencement of said next succeeding pumping stroke which startingposition is a function of said period of time.

3. A fuel injection pump according to claim 2 wherein said firstrestriction is defined between a further cut-away portion of said valvebody at said one end thereof and the wall of said sleeve.

4. A fuel injection pump according to claim 3 wherein said furthercut-away portion is so shaped in relation to the wall of said sleevethat the restriction afforded thereby is variable by angular adjustmentof said sleeve.

5. A fuel injection pump according to claim 2 wherein said valve body isdisplaceable in a direction normal to the direction of reciprocation ofsaid pumping piston.

6. A fuel injection pump for an internal combustion engine comprising ahousing, a cylinder within said housing, a piston reciprocable withinsaid cylinder by said engine to form a pumping assembly having a pumpingstroke of the piston during at least a part of which fuel is injectedinto an engine cylinder and a suction stroke during which no fuel isinjected to said engine cylinder, an enlargement of said pumpingcylinder providing an auxiliary cylinder, an enlargement of said pistonreciprocable in said auxiliary cylinder by said engine, a first fuelinlet passage opening into said pumping cylinder at a locationblanked-off by said pumping piston during a pumping stroke to define thecommencement of the period of injection of fuel to said engine cylinderand opening to the exterior of said housing for connection to a lowpressure fuel supply, a second fuel inlet passage opening into saidauxiliary cylinder at a location blankedoif by said auxiliary pistonduring a pumping stroke to generate a fuel pressure in said auxiliarycylinder and I": opening to the exterior of said housing for connectionto said low pressure fuel supply, a governor sleeve in said housingcommunicating at one end with the exterior of said housing forconnection to said low pressure fuel supply, a first pressuretransmitting passage extending between said auxiliary cylinder and theother end of said sleeve opposite to said one end to transmit saidgenerated fuel pressure to said sleeve, a non-return valve in said firstpressure transmitting passage to prevent escape of said generated fuelpressure from said sleeve through said first pressure transmittingpassage to said auxiliary cylinder during a suction stroke of saidpumping piston, a second pressure transmitting passage extending fromsaid other end of said sleeve to said auxiliary cylinder to permit theescape of said generated fuel pressure from said sleeve during theperiod of time between the end of a pumping stroke of said piston andthe commencement of the next succeeding pumping stroke of said pumpingpiston, a first restriction associated with said second pressuretransmitting passage to control the escape of said generated fuelpressure from said sleeve during said period of time whereby the fuelpressure at said other end of said sleeve at the commencement of saidnext succeeding pumping stroke of said pumping piston is a function ofsaid period of time, a third pressure transmitting passage extendingfrom said pumping cylinder and opening to the interior of said sleeve ata first location intermediate the length thereof, a fourth passagecommunicating with the exterior of said housing and opening to theinterior of said sleeve at a second location intermediate the lengththereof, a cylindrical valve body disposed in said sleeve with one endexposed to said generated fuel pressure and displaceable away from saidother end of said sleeve, a reduced diameter portion intermediate thelength of said valve body defining with the wall of said sleeve anannular chamber operable to place said third and fourth passages incommunication to terminate injection upon a first predetermineddisplacement of said valve body away from said other end of said sleeve,a radial bore in said valve body opening to the side wall thereof, anaxial bore in said valve body extending from said one end thereof tosaid radial bore, a fiat formed on the side wall of the body incommunication with said radial bore and defining, with the wall of saidsleeve, a second restriction operable upon a second predetermineddisplacement of said valve body away from said other end of said sleeveto place said one end of said valve body in communication with said oneend of said sleeve to permit a restricted escape of said generated fuelpressure, said second predetermined displacement being greater than saidfirst predetermined displacement and spring means opposing displacementof said valve body under the influence of said generated fuel pressureto move said valve body during said period of time to a startingposition at the commencement of said next succeeding pumping strokewhich starting position is a function of said period of time.

7. A fuel injection pump for an internal combustion engine comprising ahousing, a cylinder within said housing, a piston reciprocable withinsaid cylinder by said engine to form a pumping assembly having a pumpingstroke of the piston during at least a part of which fuel is injectedinto an engine cylinder and a suction stroke during which no fuel isinjected to said engine cylinder, an enlargement of said pumpingcylinder providing an auxiliary cylinder, an enlargement of said pistonreciprocable in said auxiliary cylinder by said engine, a first fuelinlet passage opening into said pumping cylinder at a locationblanked-off by said pumping piston during a pumping stroke to define thecommencement of the period of injection of fuel to said engine cylinderand opening to the exterior of said housing for connection to a lowpressure fuel supply, a second fuel inlet passage opening into saidauxiliary cylinder at a location blankedoff by said auxiliary pistonduring a pumping stroke to generate a fuel pressure in said auxiliarycylinder and opening to the exterior of said housing for connection tosaid low pressure fuel supply, a governor sleeve in said housingcommunicating at one end with the exterior of said housing forconnection to said low pressure fuel supply, a first pressuretransmitting passage extending between said auxiliary cylinder and theother end of said sleeve opposite to said one end to transmit saidgenerated fuel pressure to said sleeve, a non-return valve in said firstpressure transmitting passage to prevent escape of said generated fuelpressure from said sleeve through said first pressure transmittingpassage to said auxiliary cyilnder during a suction stroke of saidpumping piston, a second pressure transmitting passage extending fromsaid auxiliary cylinder and opening to the interior of said sleeve, athird pressure transmitting passage extending from said pumping cylinderand opening to the interior of said sleeve at a first locationintermediate the length thereof, a fourth passage communicating with theexterior of said housing and opening to the interior of said sleeve at asecond location intermediate the length thereof, a cylindrical valvebody disposed in said sleeve with one end exposed to said generated fuelpressure and displaceable away from said other end of said sleeve in adirection normal to the direction of reciprocation of said pumpingplunger, a reduced diameter portion intermediate the length of saidvalve body defining with the wall of said sleeve an annular chamberoperable to place said third and fourth passages in communication toterminate injection upon a first predetermined displacement of saidvalve body away from said other end of said sleeve, a cut-away portionat said one end of said valve body defining with the wall of said sleevea first restriction placing said second passage in communication withsaid other end of said sleeve to permit the restricted escape of saidgenerated fuel pressure through said second passage during the period oftime between the end of a pumping stroke of the pumping piston and thecommencement of the next succeeding pumping stroke of said pumpingpiston whereby the fuel pressure at said other end of said sleeve at thecommencement of said next succeeding pumping stroke is a function ofsaid period of time, a radial bore in said valve body opening to theside wall thereof, an axial bore in said valve body extending from saidone end thereof to said radial bore, a fiat formed on the side wall ofthe body and communicating with said radial bore and defining, with thewall of said sleeve, a second restriction operable upon a secondpredetermined displacement of said valve body away from said other endof said sleeve to place said one end of said valve body in communicationwith said one end of said sleeve to permit a restricted escape of saidgenerated fuel pressure, said second predetermined displacement beinggreater than said first predetermined displacement and spring meansopposing displacement of said valve body under the influence of saidgenerated fuel pressure to move said valve body during said period oftime to a starting position at the commencement of said next succeedingpumping stroke which starting position is a function of said period oftime.

References Cited in the file of this patent UNITED STATES PATENTS3,027,843 Raibaud Apr. 3, 1962 3,044,404 Bessiere July 17, 19623,075,509 Friedlander Jan. 29, 1963 3,079,862 Raibaud Mar. 5, 1963FOREIGN PATENTS 1,185,828 France Feb. 16, 1959 1,234,133 France May 16,1960

1. A FUEL INJECTION PUMP FOR AN INTERNAL COMBUSTION ENGINE COMPRISING AHOUSING, A CYLINDER WITHIN SAID HOUSING, A PISTON RECIPROCABLE WITHINSAID CYLINDER BY SAID ENGINE TO FORM A PUMPING ASSEMBLY HAVING A PUMPINGSTROKE OF THE PISTON DURING AT LEAST A PART OF WHICH FUEL IS INJECTEDINTO AN ENGINE CYLINDER AND A SUCTION STROKE DURING WHICH NO FUEL ISINJECTED TO SAID ENGINE CYLINDER, AN ENLARGEMENT OF SAID PUMPINGCYLINDER PROVIDING AN AUXILIARY CYLINDER, AN ENLARGEMENT OF SAID PISTONRECIPROCABLE IN SAID AUXILIARY CYLINDER BY SAID ENGINE, A FIRST FUELINLET PASSAGE OPENING INTO SAID PUMPING CYLINDER AT A LOCATIONBLANKED-OFF BY SAID PUMPING PISTON DURING A PUMPING STROKE TO DEFINE THECOMMENCEMENT OF THE PERIOD OF INJECTION OF FUEL TO SAID ENGINE CYLINDERAND OPENING TO THE EXTERIOR OF SAID HOUSING FOR CONNECTION TO A LOWPRESSURE FUEL SUPPLY, A SECOND FUEL INLET PASSAGE OPENING INTO SAIDAUXILIARY CYLINDER AT A LOCATION BLANKED-OFF BY SAID AUXILAIRY PISTONDURING A PUMPING STROKE TO GENERATE A FUEL PRESSURE IN SAID AUXILIARYCYLINDER AS A FUNCTION OF ENGINE SPEED AND OPENING TO THE EXTERIOR OFSAID HOUSING FOR CONNECTION TO SAID LOW PRESSURE FUEL SUPPLY, A GOVERNORSLEEVE IN SAID HOUSING, A FIRST PRESSURE TRANSMITTING PASSAGE EXTENDINGBETWEEN SAID AUXILIARY CYLINDER AND SAID SLEEVE TO TRANSMIT SAIDGENERATED FUEL PRESSURE TO SAID SLEEVE, A NON-RETURN VALVE IN SAID FIRSTPRESSURE TRANSMITTING PASSAGE TO PREVENT ESCAPE OF SAID GENERATED FUELPRESSURE FROM SAID SLEEVE THROUGH SAID FIRST PRESSURE TRANSMITTINGPASSAGE TO SAID AUXILIARY CYLINDER DURING A SUCTION STROKE OF SAIDPUMPING PISTON, A SECOND PRESSURE TRANSMITTING PASSAGE EXTENDING FROMSAID SLEEVE TO SAID AUXILIARY CYLINDER TO PERMIT THE ESCAPE OF SAIDGENERATED FUEL PRESSURE FROM SAID SLEEVE DURING THE PERIOD OF TIMEBETWEEN THE END OF A PUMPING STROKE OF SAID PUMPING PISTON AND THECOMMENCEMENT OF THE NEXT SUCCEEDING PUMPING STROKE OF SAID PUMPINGPISTON, A FIRST RESTRICTION ASSOCIATED WITH SAID SECOND PRESSURETRANSMITTING PASSAGE TO CONTROL THE ESCAPE OF SAID GENERATED FUELPRESSURE FROM SAID SLEEVE